1.x^3+1-x^2-x
=（x^3-x)+(1-x^2)
=x(x^2-1)+(1-x^2)
=(x-1)(x^2-1)
=(x-1)(x+1)(x-1)
=(x+1)(x-1)^2
2.1-a^2+4ab-4b^2
=-(-1+a^2-4ab+4b^2)
=-[(a-2b)^2-1]
=-(a-2b+1)(a-2b-1)
3.x^2-4xy-12y^2
=x^2-4xy+4y^2-16y^2
=(x-2y)^2-16y^2
=(x-2y+4y)(x-2y-4y)
=(x+2y)(x-6y)
4.2x^2-5x-3
=(2x+1)(x-3)……………………十字相乘法,了解具體的看百科
5.（2x+3）^2-（4x-1）^2
=（2x+3+4x-1)(2x+3-4x+1)
=(6x+2)(4-2x)
=4(3x+1)(2-x)
6.6xy-9x^2+1-y^2
=-9x^2+6xy-y^2+1
=-(9x^2-6xy+y^2-1)
=-[(3x-y)^2-1]
=-(3x-y+1)(3x-y-1)
7.3x^3-12x^2y+12xy^2
=3x(x^2-4xy+4y^2)
=3x(x-2y)^2
最后1題你再看看.有錯嗎?